<p>I am a rising senior and am interested in some competitions. These include the Intel STS, Siemens, USABio, and the like. Just out of curiosity, if I do well in these competitions, will it matter for college admissions? Many of them don't announce the results until March-June, and by then it will be too late to have any impact. Is this true? Thanks.</p>
<p>Yes, it will likely be to late to have any impact–decisions for most competitive schools, after all, come out March 31/April 1. I wouldn’t do these competitions if your primary motivation is college apps, especially since they can be time consuming during a time when you need to be focusing on maintaining your grades and finishing apps.</p>
<p>Siemens competition results are October/November, well before application deadlines. STS results are usually January-ish, but you can let colleges know via your midyear report. As for the math/science olympiads, they most likely will not affect admissions (unless you are on some waitlists - then they might have some impact).</p>